SuperEarth
by Captain Sigma - Karry Beta
Summary: After leaving Kara behind, Barry thinks he made it home. He's wrong. In a world similar and yet completely different, Barry must team up with another version of a good friend and fight a foe who just won't die. Will he make it home this time? And can he stop Zoom now both are stuck on SuperEarth? - Three chapter follow-up to Supergirl's "Worlds Finest".
1. Stranger than Fiction

_A/N:_ _So working with CharmedMillie on her extremely popular Karry One-Shots (now known as Karry Universe) and in the build-up for the Supergirl/Flash crossover I had this insanely awesome dream of what that crossover could be. Of course it was nothing like what we were shown (which in itself was more than awesome), the dream stayed with me and, talking to various friends, I decided to make it into a FanFiction! Tied in to Flash we know, the Supergirl/Flash crossover and a large dollop of something new altogether I finally came up with a three-chapter story of my own. I really hope you enjoy and understand what's going on. Be sympathetic and review, please._

 _Disclaimer:_ _I own nothing. Wish I did though. Damn you CBS/CW/DC…_

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 **Chapter One – Stranger than Fiction.**

It had worked, he was sure of it. All he needed to do was stop. Just stop.

He couldn't – hurtling out of the vortex between worlds at top speed, Barry's legs were out of control and he could barely keep track of where he was going until…

" _What?"_

He was suddenly in the air. No ground under his feet. Had he run so fast he had managed to get airborne? He certainly hadn't run up a building to do so.

"I don't know who you are but I have enough on my plate with your blue friend," the voice was familiar as Barry looked around as best he could.

"Kara?!" Barry exclaimed, seeing the familiar face, he now confused. He had just left her. He had been so sure he had gone to his home universe. Why was she here?

"You know me?" the girl in the blue and red costume almost stopped, her concentration broken.

"We just… can you put me down?" Barry asked, trying to catch up with what was just happening. Did he run into the past of her Earth, maybe? Is that why Kara didn't know him?

"Not until we get to the DEO!" Kara stated, shouting a little over the slipstream.

"Been there – we're going in the wrong direction though," Barry amused himself, letting himself hang in Kara's grasp now as they headed a direction he recognised from another world altogether. "Wait, that's STAR Labs!" he cried in shock as the familiar circular building flew below them, Kara suddenly circling it before landing. "Why's the DEO in STAR Labs?" Barry now insisted to Kara, who grabbed his wrist, ignoring the question as she led him in to the familiar halls.

The halls were the only thing recognisable about the place though; inside, the labs were changed, there were military personnel all placed at strategic intervals and all pointed their weapons at Barry, who raised his free hand in surrendering worried as he was lead to a middle-aged man with a strong jaw and dark hair.

"Jeremiah Danvers, head of the DEO," he introduced himself importantly to Barry, who couldn't quite take in what he was seeing, but things were slotting into place. "I see you've met my daughter."

"Daughter?" Barry repeated dumbfounded, glancing back to Kara who looked resolutely at Barry. He knew a bit about Kara's Earth and he knew for sure Lucy Lane was head of the DEO. She had definitely been so when he was there barely half an hour ago. He had an idea he knew what was going on now though. "I'm sorry, I don't know what –"

"We don't know if you're a friend, accomplice or partner to our blue blur but having you in our facility should work to our advantage. Well done, Supergirl," Danvers addressed Kara, pleased as someone grabbed Barry's arms, he felt handcuffs being placed on his wrists as he looked worriedly to the apparent head of the DEO.

"Blue blur…?" he asked tentatively, a sinking feeling in the pit of his stomach as, without another word from the head of the DEO he was lead to the pipeline.

It seemed he had landed on another Earth, one where the DEO and STAR Labs were one and the same, which meant that Harrison Wells or Cisco Ramone or even Caitlin Snow must be around here somewhere. And there was a blue blur terrorising the city. Or cities. That meant only one thing, unless Velocity 9 was freely available to this world: Zoom had found this Earth. Barry needed to cooperate, and get himself free as soon as possible.

"I'm not a friend of your blue blur, quite the opposite in fact," Barry pointed out to the person leading him to the pipeline – a woman with short black hair and a look of concentration shared only with Kara Danvers. Or at least this Earth's version of Kara Danvers.

"Then why do you possess the same powers?" the woman asked, the door to a cell being opened as Barry had to act quickly, without being his natural speed, of course. He didn't want to freak them out more than he apparently already was.

"Because he and I come from different worlds, we were both exposed to the same sort of… radiation which is where we got our powers, but he's been terrorising my Earth for months now, and I'm the only one who can stop him! Please…" it hadn't worked though, he found himself within a cell, reflecting back on the recent event in which Trajectory managed to lock him up like now.

The woman however remained outside the cell as she looked to Barry, seemingly with deep thought before she finally asked: "How do you know my sister?"

"Sister?" Barry asked, dumbfounded. "Who's your sister?"

"Kara. Supergirl" she stated, annoyance now in her voice.

"Oh my god!" Barry responded, grinning as he stated excitedly: "You're Alex! I'm glad to have finally meet you, well a version of you anyway."

"A version…?"

"It's like I said. Look, do you have Harrison Wells working here? Or Cisco Ramone? Maybe Caitlin Snow?" Hopefully one of these familiar faces, although alternative to the people he knew, would be more understanding.

"Doctor Caitlin _Raymond_ " Alex put emphasis on the new last name, causing Barry to smirk in spite of himself at the implications that could mean, "left a while back, but we do have Mr. Wells and Ramone, yes" Alex replied, stiffly.

"Please get me Wells," Barry begged, going the extra mile to actually clasp his bound hands together in full-out begging mode and then, to show he meant no harm, removed his mask to reveal his full face.

"Okay" Alex replied finally. "But I'm not letting you out." She turned and left the room, Barry letting out a relieved sigh as he slumped back on the wall, worry now beginning to spread through him; how long had Zoom been here? If he could travel to this Earth, how many others had he been to? What state would Barry find his Earth when he eventually got back there? Would he return home? It wasn't exactly like he could set coordinates to get back easily; each time was literally a leap of faith.

"So what do we call you?" Barry looked up and, for the first time in his life, was grateful to have Harrison Wells in his line of vision. Well a version of him at least. Behind him were Alex, Jeremiah and Kara – still in full Supergirl outfit. Now Barry had his mask off and she could see his face, she looked slightly shy, which was weird. If she was anything like the first Kara Danvers he met, she'd be geeky, awkward and happy but never directly shy.

"I'm Barry Allen sir," Barry addressed Wells "and I'm from an alternative Earth."

"Alternative Earth?" Wells asked, intrigued but doubtful.

"Yes. On my Earth I know you, well I know two you, well sort of. It's a long story. But the you I know, the current one, has a daughter, Jesse, who you love more than anything on any world." He hoped this Wells was of the same make; if he was a disguised Eobard Thawne though…

"I have two daughters," Wells stated abruptly. "One is indeed called Jesse. What has this to do with you, Mr. Allen?"

"I'm just trying to gain your trust and trying to explain the multi-verse theory, which is actually fact," Barry spoke at top speed, his eyes locked on Wells as he ignored the three Danvers'.

"I know of the multi-verse theory," his voice remained level, "you have hundreds, thousands of different Earths, all vibrating at different frequencies –"

"That if you can run fast enough you can breach between the worlds and land in a different frequency, which is what I have done and seem to be getting better at. Sort of. It's what Zoom's managed to do, who, might I add, I'm in no way affiliated with."

"Zoom. Yes, that is what he called himself. Would you by chance go by the name 'Flash', Mr. Allen?"

"Yes! How do you know?"

"Because that's what, or who it seems, Zoom has been demanding."

"And for someone who can run fast, he seems to be a somewhat-match for me," Kara suddenly spoke up, adding, "you know, flying too…"

"And heat vision, freeze breath and super strength. You like to punch," Barry added with a smirk. "Like I said: I come from another Earth and have literally come from a world where I already met Supergirl, been in the DEO, and even met the infamous Cat Grant." Barry tried to namedrop, hoping to convince everyone.

"Was she as infuriating on that Earth as this?" Kara asked, unable to help herself.

"More like self-centred, arrogant and yet somehow endearing. She was like a… well, a mentor to you," Barry pointed out, about to use a parental reference but with her foster dad and sister in the room, that would have been a bad move.

"You believe he is who he says she is, Miss Danvers?" Wells asked turning to her now; even on this Earth he didn't call people by their alternative names either, it seemed.

"Yeah," Kara smiled looking at Barry. "I do. At the very least he didn't mean to end up here, having literally arrived when I picked him up."

"In which case" Jeremiah stated, he having remained at the back, behind Wells, Alex and Kara, watching over events, "I trust that you won't put us to harm, 'Flash'?"

"I'll even willingly work with you to take down Zoom!" Barry pointed out, trying to be helpful.

"That maybe sooner than you think," Alex spoke up, she having been distracted the past minute or so as she moved over to the monitor on the wall. On Barry's Earth it was a simple on/off switch to access the cells in the pipeline; here it doubled as a television too, it seemed. Or at least a clever tablet.

' _Blue Streak terrorises National City. Demands 'Flash' again'_ the banner on the news article read as Barry saw Zoom had about a hundred innocent citizens trapped in the large familiar park he'd recently fought Silver Banshee and Livewire in on the other Earth. Burning on the grass in large letters were the words 'Bring Me Flash'.

"Let me out" Barry voiced, his voice surprisingly level as his brain boiled in anger.

"We fight him together," Kara pointed out, Barry forcing his eyes away from the small monitor to look at Kara. Reluctantly he nodded.

"Together" he stated as Wells went to open the cell. Once out he held out his hand to Kara who took it in a handshake. It seemed that for the second time that day he was once again partners with Supergirl.

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 _A/N: Hope you enjoyed! Next chapter: 'Zoom V SuperFlash'. Please REVIEW._


	2. Zoom V SuperFlash

_Note:_ _Apologies for the wait for this next chapter; I had another story that took priority. I also notice a few of you asking how this Earth works in comparison to the ones we know from_ The Flash _and_ Supergirl _; to answer that, if I can't work elements into the story I shall be adding a fourth 'chapter'of footnotes on how exactly I picture this Earth and elements of intertwining histories. Anyway, hope you enjoy and please review. Thank you._

 _Disclaimer: Although I don't own anything or anyone from _ Supergirl _or_ The Flash _, I believe I own the idea for this version of Earth, so… yeah._

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 **Chapter Two - Zoom V SuperFlash.**

As a golden-red blur zoomed through Central City and a blue-red streak shot across the skies above, Barry Allen was already regretting taking Kara Danvers with him in his vendetta against Zoom. She had agreed and if she were anything like her Earth-3 counterpart, she would be a valuable asset against the man in blue; still, he was already thinking back the conversation he'd had only moments ago with her and the DEO…

"Before you go running off, perhaps it's better to have a plan, Mr. Allen?" Wells had pointed out, mere seconds before Barry prepared to leave STAR Labs to get to Zoom – he'd even already put his mask back on.

"My plan is to stop him," said Barry simply, looking briefly at Harrison Wells as he turned to look to Supergirl, about to nod an indication that they should leave.

"And how exactly will you do that?" Jeremiah had pointed out, Barry resisting the urge to shout at the man that innocent people were in danger, once again, because of _him._ But Kara responded first;

"Catch the bad guy. Eighty-five percent chance of punching. A possibility of freezing too." Kara said almost the exact same line she had said on the Earth-3 before rushing out without a plan. Barry couldn't help but smile, and then frown as the words left her lips, remembering how well that went last time. This was different, though. This was Zoom. There was no time to plan.

"I've got to stop him," Barry now addressed Jeremiah, keeping his voice calm in spite of himself. "There are innocent –"

"There are always innocent lives at risk," Wells had now spoken up. "It's how you _plan_ to save them that allows salvation. You're hot headed and blind-sighted, just like Miss Danvers can be!" Wells hadn't raised his voice, but Barry felt like he had been shouted at, and for a moment his mind had gone blank.

"We should capture him," Kara had spoken up behind Barry, ignoring Wells' insight. "I can freeze him and we can put him in one of the cells like we've done the others. Together Barry and I will be quick enough to get him –"

"Others? You have meta-humans here?" Barry turned to look at Kara now, but it was Alex who answered;

"I don't know about 'meta-humans' but we have a few aliens in lock up in the pipeline."

Barry had remembered at this point from his visit to Earth-3 that there had been a downed Kryptonian prison ship; it seemed the same thing may have happened here. His thoughts to Zoom lulled at this point by curiosity as he turned to address Harrison.

"Did you ever activate the particle accelerator?"

"No. I shut it down an hour before it was due to start," Jeremiah had replied to this, "and the DEO claimed it as a base not long after that. Which is why we use the pipeline to trap our enemies, which brings us back to Zoom."

"Right. Yeah. Zoom… err," Barry looked back to Wells as a thought passed by his mind. "He can phase through objects. Like solid walls."

"He can walk through walls?" Alex was shocked by this, but kept quiet as Barry continued.

"The cells wouldn't be able to hold him, not by far but –"

"If we could find a way to vibrate a cell to a level in which he can't pass through, we can contain him," Wells concluded, ignoring the looks of shock on Kara and Alex's faces.

"Yeah, for a while anyway. But I've _got_ to catch him first," Barry pointed out, looking back to the small monitor – the article hadn't changed, apart from the addition of the words ' _National City looks to Supergirl for help_ ' – Supergirl, of course, had yet to show up at the scene.

"I need to know how fast Zoom can run to even get an idea on how to manipulate one of our holding cells – you need to keep Zoom occupied and make him run his ultimate speed before we can even consider capturing him," Wells pointed out.

"We can do that," Kara spoke now, stepping up and next to Barry. "If we can get him away from the cities, out in the wastelands where he can't hurt anyone, we can get him to run his fastest." She had been smiling by that point and Barry couldn't help but grin back at her.

"Then I shall need my lab, access to one of our strongest cells, and Mr. Ramone." This had been directed to Jeremiah, who nodded instantly as Wells looked back to Barry and Kara as he added: "What are you two waiting for? Run!"

And so Barry and Kara found themselves heading to National City. It was a bit of a shock for Barry to realise the two cities, National and Central, on this Earth were practically one and the same – although he had no time to ask how – which meant that National was a mere few seconds away for him than it would have been on his Earth or Earth-3 and when he came to halt in the park, stopping before the still-burning flames on the green, he finally came face-to-face with Zoom once more.

"Flash," the man in blue, whom had been circling the civilians he'd been enclosing as bait for the past few minutes, stopped directly in front of Barry.

Barry looked at the man anger rising inside him again. Now that he knew who was behind the mask, it had gotten personal. He had trusted the wrong person yet again and so this was his fault. All his fault. "Jay," Barry whispered anger in his eyes.

"Debatable" Zoom growled, glancing upwards as a rush of cold air blew out the burning lawn – Kara had used her freeze breath. "You came with a friend. She will witness your death before I rip her apart!" Zoom taunted.

"I'll like to see you try," Supergirl mocked from above, her Kryptonian physiology would have proven hard to break, even for Zoom.

"Leave those people alone," Barry stated calmly, ignoring the threat, although his anger was at boiling point again. "It's me you want. Supergirl comes with the package here."

"Supergirl," Zoom repeated, "that's what they call you. How pretentious."

"Are we just going to stand here and chat or…?" Barry didn't bother finishing this sentence as he turned on his heel and ran, knowing instantly Zoom was following.

His past-encounter with the Reverse Flash had given him the physics he needed to run faster than ever, and while he was getting better, he knew Zoom could easily out-run him. But fear and adrenaline kept him going as he sensed, rather than saw the man at his tail. He looked up to see Kara speeding above him, slightly faster as she didn't have any obstacles to run around as they lead Zoom out of the cities; he could see the wastelands outside the border rushing toward, and then passed him as he gained momentum, Zoom getting even faster.

He'd never actually felt so alive.

"NO!" Kara screamed from above as she looked down to see Zoom catch up with Barry, the Flash suddenly stopping as his body went flying with built-up momentum. Instinctively Kara swooped down, grabbed Barry before Zoom could reach him, and still kept flying.

Looking down at Barry in her arms, she realised Zoom had only just knocked him out – for one horrible moment she had thought Zoom had killed him – before looking below. Zoom was still following. He'd wanted the Flash, but Barry hadn't divulged why. She'd never gotten to ask.

"I hope he's at his fastest!" Kara called into her earpiece to her DEO colleagues, "because I don't think he's tiring and Barry's out cold. How long can you give me?"

"Five minutes," the voice of Cisco Ramone rang in Kara's right ear as she grinned. "Is that all?"

"Harry and I have calculated the speed and are applying what we need to the cell. It needs to be… well, it's complicated, alright! Keep Zoom distracted until we give the all-clear."

"You have my word," Kara responded; they were reaching the Bay now, having circled around the cities about three times now in those few short seconds. "Now, Mr. Zoom, let's see if you can run on water…" flying directly to the Bay, Kara looked below in shock as the blue man rippled across the water's surface like it was solid ground.

"You've got to be kidding me!" Kara now groaned.

Another idea passed through her head as she stopped, inhaled, turned and blew out a jet of freezing cold air upon both the ocean below and the figure; in spite of his speed he began to slip, and started to slow down. Kara didn't stop as she circled the man, quickly encasing him in a rough block of ice.

"That won't hold you for long…" Kara muttered from personal experience, more to herself as the ice block containing Zoom began to sink below the waves. She had tried similar tactics on Zoom before Barry had shown up and it honestly hadn't taken him long to escape. Her freeze breath seemed to be the best weapon against the speedster, though, but it just didn't last for long.

"Come on Cisco…" she still had an unconscious Barry in her outstretched arms and didn't comprehend how far out to sea she had gotten until she realised she could no longer see land. "Oh. Great."

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 _Note: Nice cliffhanger there. Again, I hope you enjoyed this. Final chapter: 'Worlds Finest, Take Two'. Please REVIEW._


	3. Worlds Finest, Take Two

_Note:_ _So, final chapter. I definitely think this is the best of the three and I hope you all enjoy reading it as much as I have writing it. Big shout out to my Beta, CharmedMilliE – Karry Master, for helping me expand this story and making it what it is now; and for all her Karry Universe fics for continuously inspiring me for this particular story. I should also add that the 'footnotes' to this story will be uploaded in a few days explaining how this universe is formed and whatnot, so if you have any questions you want answered about 'SuperEarth', write them in the reviews and I'll be sure to answer them in the footnotes. Right. To business!_

 _Disclaimer:_ _Read chapter two's disclaimer… ;-)_

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 **Chapter Three – Worlds Finest, Take Two.**

"Who are you?" Jeremiah Danvers stood in front of Wells' revamped holding cell in the pipeline, his biological daughter by his side as they both glared at Zoom. Unlike Barry he hadn't removed his mask but had made several as-yet unsuccessful attempts at escaping his temporary prison, hitting the various walls and seeming to vibrate himself beyond the realms of vision to get out.

"What are you?" Zoom hadn't replied. Having failed to get out he now just stood, staring intimidatingly – albeit despite they not being able to see his face – at the DEO head. He's remained silent however. Most likely calculating when, or how, he could get out of his confinements. It had obviously been a long time since he was in such situation, it seemed.

"Why are you here?!" Jeremiah almost shouted this, frustrated at getting nowhere. He had never had this much problem with a prisoner before. Even Astra had been more talkative when they had her.

Ever since Kara had delivered the partially defrosting block of ice containing the speedster, Jeremiah and Alex had remained in his presence, watching him, trying to keep him in check, studying him, almost. As best as they could of course. Kara, meanwhile, had vanished with the unconscious body of Barry to Wells' lab.

"Why. Are. You. Here?" Alex now repeated her father, almost growling through her teeth and Zoom finally turned his attention to her; progress it seemed.

"Trapped," he finally growled, a single-word answer.

"Trapped? Here?" Jeremiah spoke up. "Is that why you needed the Flash?"

"Flash is not of this world," another simple reply, albeit on-point.

"Neither are you. Were you trying to use him to get back to your world? To his world?" Alex spoke before her father could.

"I need Flash. I need speed!" At this, Zoom hit the glass of his cell and Alex could have sworn one of his fingers passed _through_ the solid substance. She hoped not, after all, Barry had said he could _phase_ through walls.

 **-SuperFlash-**

Barry had been stripped of his outfit, lying under a sheet on a make-shift hospital bed in Wells' lab – the very same room Caitlin had had Barry unconscious in a few times on Earth-1 – with Cisco Ramone and Kara looking down at his sleeping form.

"What did Zoom do to him?" Kara asked, a quiver in her voice.

"It's hard to tell," Cisco was the one to answer, "but he heals at superior speed. There are fractures all over his body, which look years old but could have been made in the last few months to a year. His back too. I guess it's not an easy life being the Flash…"

"Well, unlike Miss Danvers here, Mr Allen can break," Wells pointed out, moving over to the pair and Barry with a syringe. "Whatever happened to him allowed him the ability to recover quickly to fight another day, but I suspect whatever Zoom did, if it wasn't for your intervention 'Supergirl', we may indeed have a corpse on this bed than an unconscious young man."

As he spoke, Wells took a sample of Barry's blood. Kara looked to the small syringe with curiosity but didn't verbally question the professor as he moved back to his instruments. "Let's just hope he awakens soon as I doubt mine or Mr Ramone's updating on Zoom's personal cell will last."

"Zoom…" Barry groaned from the bed, turning his head on the pillow.

"Barry?" Kara asked tentatively, she reached for his hand under the sheet.

"Zoom!" Barry sat up, Kara withdrawing her hand quickly as he looked around in desperation. "Doctor Wells? Cisco? What…?" Barry's eyes fell on Kara and it seemed things slotted back into his mind as he reached for his head with both hands, cupping his forehead and groaning. "Please tell me he didn't get away?" He asked to the sheet now just covering his legs.

"We got him," Kara responded instantly. "He… did something to you but we managed to get him locked up, temporarily anyway."

Barry removed his hands to look at Kara. "Temporarily?"

"It won't take your Zoom friend long to find the right frequency to vibrate out of his containment and most likely come for you, Mr Allen." Wells returned to the bed's side, his bedside manner the same as his parallel self from Earths 1 and 2 – non-existent.

"He's _not_ my friend" Barry pointed out, although not looking to Wells as he continued to stare, almost intently, at Kara, who blushed and looked at Wells herself.

"But we have some time to get actual answers from yourself, _Barry,_ " Wells added, forcing Barry to look from Kara to Harry, an eyebrow raised as he simply nodded, wanting to get Harry's questions over with. "Such as," Harry moved slightly closer, Cisco moving back instinctively, "how you came to be the Flash and why Zoom is after you."

Barry sighed. From the moment he'd landed in this strange DEO/STAR Labs merger he'd known he'd be asked this question, and he had his answers ready without really knowing it. "On my earth, when you turned on your Particle Accelerator it went wrong, malfunctioning during its public unveiling and bathed the city, Central City, in an unknown form of radiation during a severe and freak thunderstorm; I was struck by lightning and as a result gained my speed – it affected others in the city though, hundreds, if not thousands of civilians gaining super-powers from whatever elements surrounded them. We call them meta-humans."

"Is that what happened to Zoom?" Cisco breathed from Harry's side.

"Similar. On another Earth, a parallel Earth. Only he wasn't happy with what he was given. He wanted to go faster, but didn't want to work for it in the way I have; by training and pushing myself to go faster. He simply doesn't care who he hurts in his goal for ultimate speed, though."

"And that's why he wants you," Wells concluded, "to gain your speed?"

"Yeah," Barry looked down from Wells to the floor. "I think he's been breaching universes to find other Flashes to steal their speed. It's how he found me and how he killed… killed another Flash." He didn't want to say Jay's name. He still wasn't sure if Zoom was the same Jay he'd known. Zoom had debated this identity when confronted in the park earlier, but Cisco had vibed off Jay's helmet to Zoom. That meant something, didn't it?

"You've got to go back" it wasn't a question, but there was sadness in Kara's tone as Barry now looked to her again, "to your Earth. With him." She didn't know why she was sad. She knew this was coming, but deep down she didn't want it.

"Yeah," Barry nodded, feeling strange for admitting it. "I didn't even know he was here, I got here by accident but now I know –"

"Kara!" all looked to the doorway. Alex stood there, flushed and panting. "It's Zoom!"

Barry was gone before anyone could react; putting on his suit and in front of Zoom's cell before Alex or anyone else could say a word. Guards lay unconscious, or even dead, at the entrance to the cell area and Zoom stood outside of his cell, holding Jeremiah in the air by his throat, the head of the DEO helpless as Zoom looked to Barry.

"His life or yours, Flash!" Zoom growled, his free hand suddenly vibrating at intense speeds.

"Don't," Barry warned, his heart pounding, but before Zoom could even move his free hand to Jeremiah's chest, there was a rush of air, a loud crack and Jeremiah had vanished. Zoom was holding his suddenly broken arm as Supergirl appeared next to Barry.

"He said it earlier, Zoom, here you don't face the Flash alone!" Kara snapped as Zoom stood firm against the pair, the arm Kara broke to free her foster father healing in top speed.

"Fine!" Zoom said looking between the two of them. "You both will die."

Both Barry and Kara were ready however as Zoom hurtled toward them, they both moving aside as the man in blue sped through the wall behind them, they both following as Zoom retreated out of the Labs.

"How do we get him out of here?" Kara asked Barry as they regrouped outside STAR Labs, Zoom, too, having stopped to taunt them as Barry attempted to run around the figure to throw his lightning at him – Zoom easily ran from Barry's containment.

"Would you believe we have to get him to chase us again?" Barry remarked, they both following in the chase, pursuing Zoom this time.

"And then?" Kara asked, she running this time instead of flying, next to Barry.

"Throw me when we reach our top speeds. With any luck Zoom will go after me as I form a temporary breach to my world. Hopefully my world." Zoom was paying them back for capturing him, running as fast as he could through Central City and doing as much damage as he could too – it was all Kara could do to blow out fires as she ran passed them. "But I can't guarantee he won't find a way back."

"You'll have to stop him before he does then," Kara stated resolutely as they both grinned at each other, both feeling the strong connection, that same bond Barry had felt for the previous version of Kara – this one was exactly the same as that one and, had they not been trying to save two cities from the wrath of an evil speedster, either one could have pulled the other aside for a kiss.

As it were, for the second time that day Barry felt his feet leave the ground as Kara picked him up. "I'm faster flying," she called to him as they sored over the city, following Zoom across a river to National City.

Kara was right – in the air they caught up to Zoom easier and Barry couldn't help but wonder if Zoom was actually _slower_ than he had been of late. Could it be that he hadn't had his fix, whatever that could be, while being stuck on this Earth? It was lucky if so as Kara dropped Barry to the ground ahead of Zoom and she called to him, "Ready?"

She too took to the ground again as they ran, faster than before, ahead of Zoom. "As I'll ever be!" Barry cried back as Kara, in one motion, turned, picked up the projectile that was his body and threw him.

Just like before, on Earth-3, the portal that allowed him transport between worlds opened and Barry hurtled into it, barely able to look behind him as a blue blur that was Zoom followed him in…

"Bye Barry," Kara sighed at the spot the portal had been. The Flash and Zoom had vanished from her earth at almost exactly the same moment and Kara watched, having circled back to where the blue portal had opened, with a tinge of sorrow to her heart. She'd had an instant rapport with Barry Allen the moment he'd shown himself to her in the cells at STAR Labs. Feelings she had never felt for anyone else, and even though he'd barely been in her life a day, she knew they'd both felt a connection that only those with the world on their shoulders could feel. He had Zoom to deal with, and she had the inevitable threat of her Kryptonian uncle.

Not looking back though, Kara took to the air as she headed back to the DEO, to make sure her foster dad was okay after Zoom's attack. He was tough as nails though, so he'd pull though fine.

 **-SuperFlash-**

It had been a week since Kara Danvers had seen the Flash run in, and then out, of her life and she hadn't been able to shift the thought of parallel universes. He'd met a version of her on another Earth, so could there possibly be a Barry Allen on her Earth? And if so, who was he? What did his life entail? Was he the same sort of man as the Barry she had met?

These questions all lead her to this moment. Concealed up a tree in a suburban street of Central City, looking through the branches to the house across the road as a car pulled into the drive.

The driver's side door opened and a tall man with pointed brown hair, jeans, a tee and converses slipped out. He looked distracted but he was smirking to himself as he moved to the trunk of his car and unlocked it. At that moment a middle-aged, rather handsome, man opened the front door of the house Barry Allen had pulled into and marched over to the young man by the car.

"Just a few supplies, you said!" The man accused as Barry hoisted a grocery bag under his arm and handed another to his dad. Kara didn't need to use her super-hearing to hear this, the day was clear and the rest of the street quiet.

"Well it saves you going out," Barry reasoned as he and his father moved to the front door, a woman appearing in the frame, "and gives me an excuse to see you guys."

"You were only here yesterday, young man!" the woman at the door responded, but grinned nonetheless as she pecked Barry on the cheek, "but I'm always happy to see my son. You just missed Millie though, she's gone out with Wally again."

"Oh yeah?" Barry asked Nora Allen as he put the bag in the doorway in front of her and returned to his car, his dad lingering with a grocery bag under each arm as Barry got the fourth – and last – bag of food from his car, closing and locking the vehicle after. "She and Wally have been getting awfully close of late. I may have to speak to Iris…"

"Oh they're just friends," Nora commented absently as she picked up the bag Barry had left in front of her.

"You're honestly not falling for that are you?" Henry asked his wife as he waited for her to move back so he could take the food bags inside. "She's a rebellious teenager going out with an older man!" Kara could hear his voice call from the doorway.

"She's _our_ rebellious teenage _daughter_ going out with Iris' little brother. We've known the boy since he was a baby," Nora noted as she followed him in, Barry shaking his head as he moved over the threshold of the house and closed the door behind him.

Smiling from the tree at the perfect family moment, Kara however braced herself as she gently fell from the tree, landing noiselessly on the pavement and brushing the odd twig out of her hair and cardigan – she'd literally flown from work across the river to come to the Allen house, their unexpected visitor – before crossing the empty street and pausing a moment in parallel to the back of Barry's car. She assumed his dad's vehicle was parked in the garage.

"Okay Kara. A new friend. Just introduce yourself…" she muttered as he forced herself forward, butterflies now erupting in the pit of her stomach as she now forced herself up the steps to the front door and rang the doorbell. Instantly she let out a nervous breath of air as she heard footfalls make their way back to the door. What if this was a bad idea? What if he was nothing like the man she had met? It was too late to turn around now, though.

Barry Allen appeared from behind the wood, grinning at some joke one of his parents must have said as he looked Kara up and down, his smile faltering a moment. "Hi. Do I know you?" he asked pleasantly before coughing and adding more seriously. "Sorry, that was rude, I mean can I help you?"

The butterflies vanished in Kara's stomach as she couldn't stop grinning at the man, probably unnerving him slightly as she replied. "Not yet. I'm Kara. Kara Danvers, I just thought I'd say hi… so hi," she gave him a little geeky wave on the doorstep as he spluttered a 'hi' back at her again. "Sorry, this is really stupid. Can I come in? I mean you no harm but I need to talk to you." She wasn't a hundred percent sure what she was going to say but she needed to talk to him, to find out if he was the person she hoped he was.

"Oh. Err, yeah, come in, yeah" Barry responded with a smile, stepping back as Kara entered the Allen household, the door closing behind her.

* * *

 _Note: Hope you liked. Please review and look out for the footnotes soon!_


	4. The Making of Another Earth (Footnotes)

I apologise for not uploading this sooner – I have been lacking internet for the best part of a week and only got it back some six hours ago! Anyway, where do I start?

I suppose the best place to begin with is to explain the world as a whole, or maybe even how I came up with the idea for 'SuperEarth' to begin with. Well I mentioned in the first chapter that it all started in a dream, one that was very different to how this fanfiction ended. What I remember of the dream though was similar to how the story started off, but varied differently soon after: Barry was knocked unconscious soon after he came through the portal, Kara had to overcome Zoom with no additional help and when Barry finally woke he and Kara snogged one another like in the end of one of those silly romance movies.

I blame _CharmedMilliE – Karry Master_ for that last bit, but who can blame any of us for wanting Kara and Barry together? They are pretty much made for each other on their respective shows, after all. I even hinted a probable future for SuperEarth's Barry and Kara to become something in the final segment of this story. But I'll come back to that later.

Even though I pretty much stole the worlds of Supergirl and The Flash, creating the SuperEarth of this fanfiction was damn fun and I hope you enjoyed reading it as much as I have writing it, but enough chit-chat and on to what you really wanted: A history of sorts! Please don't be distracted by the bold texts as they will help you navigate to the places and characters you want to know most about if you don't want to read this as a whole piece.

So, when it came to how I could possibly link **National City** and **Central City** , I originally thought the two would just be one big city, with the metropolis part of the city (with the skyscrapers such as CatCo and Lord Enterprises) being branded 'National' and the more downtown, slightly older part being 'Central', but upon watching _Batman V Superman_ and seeing how they placed Gotham and Metropolis on either side of a bay, the idea of doing something similar with Central and National took hold, with the final result being a river separating the two cities.

Two settlements, two different cities, parted only by a slim body of water leading directly to the ocean. Genius! Yes, each city has a beach as they're on the west coast directly by the sea ( _oh I do love to be beside the seasiiide, oh I do like to be beside the seeeeeeea…_ ahem, sorry.) Now, why they never merged to become one city as originally thought is simply down to politics. I'd imagine no-one would want to go through the massive pain of changing one city to another under a singular name, so to keep each separate, maybe sharing an underground train network and several linking bridges, was enough for both cities.

When it came to the histories of the two separate capitals, they share many similarities to their TV counterparts (especially Central) but as hinted at in the story, that's where it ends. For instance, the Particle Accelerator was never switched on, so there are currently no meta-humans in either Central or National but there _are_ people such as Livewire and Silver Banshee (exactly the same history there as in Supergirl) to keep Kara distracted.

The histories of many of the characters are similar too, such as **Kara** 's is pretty much unchanged, except for when it comes to the **DEO** being in Central City instead of somewhere out in the wastelands around National; **Cat Grant** still is the exact same person – rising through the ranks at the Daily Planet to set up **CatCo** and eventually run the biggest media conglomerate to rival her former employer. **Alex** 's history is very different though. In this universe, as her father never died there was always more than just her to protect Kara. Alex even went into a 'normal' career path until she became bored and her dad intervened to give her a position in the DEO.

 **Jeremiah**. Ah yes, I haven't forgotten him. As we all know from the TV show he supposedly 'died' protecting **J'onn J'onzz** from the real Hank Henshaw. In this version, Hank still died like in the show but Jeremiah definitely didn't. J'onn saved Jeremiah's life (he still got stabbed by Hank though) and by so doing gained the DEO's trust enough to treat him fairly, soon-after sympathetically and eventually deemed him harmless. What J'onn is up to in the SuperEarth story during the time of Zoom and the Flash's appearance I haven't thought too much in to, but know that he's alive and well, probably with his niece, **M'gann M'orzz** (aka. Miss Martian) somewhere on Earth. Jeremiah, meanwhile, is obviously head of the DEO in J'onn's/Lucy's place, still happily married to **Eliza** and still living in the same house – although I'm not entirely sure where said house is located.

Kara still has her job as Cat **'** sPA too, and loves it. She works with **Winn** , as usual, but **James** is no-where to be seen; he remained in Metropolis to work things out with **Lucy**. I hope they're happy there now, whatever they're doing. Winn himself hasn't changed; his dad is still the Toymaker and he did date **Siobhan** (who still teamed up with Livewire to face off Supergirl, but both were defeated by the emergency services, Flash no-where to be seen to help, obviously) when Kara revealed she didn't feel the same way about him as he did about her, but there is one major difference to his backstory in this world: After his father was jailed for his crimes, like Barry in The Flash, Winn was taken in by a kind and loving family – the Ramones.

That's right, Winn and **Cisco** are brothers! A pairing I think works perfectly considering their similar attitudes. Of course this changes Cisco's past too, but not by too much. Sadly, he's still the least loved between his older brother and himself, and obviously Winn gets special attention due to his history, but at least now Cisco has someone who cares for him no matter what the rest of his family say or do. Winn and Cisco have never been closer, even if one works at **STAR Labs** in Central and the other across the river at CatCo.

As you may have noticed in the first chapter of SuperEarth, **Caitlin** and **Ronnie** have married and moved away. I loved those two as a couple and now that the Particle Accelerator never malfunctioned, Ronnie never became one half of FIRESTORM and never sacrificed his life to save Central (or the rest of the world) from being sucked into a black hole. Together, the Raymonds moved to Starling City (itself benefiting from the Arrow and friends working _with_ the police force, rather than in parallel to, and making the city safer than the TV show will ever be) where they either started their own company or took up the roles of teachers somewhere. I imagine something cushy and 'happily ever after' for them here as I doubt we'll see that for poor Caitlin on the actual TV show.

Before I move on to the biggest of differences from either show, Harrison Wells, I must make a shout-out to the **West** and **Allen** clans. **Francine** , indeed, left **Joe** while pregnant, but came back into Joe and **Iris** ' lives much earlier; although Joe could never forgive her, she'd sobered up and helped raise both Iris and Wally, albeit separated from Joe.

Meanwhile, for whatever unknown reason, the **Reverse-Flash** (still existing in the future of even this Earth) never made it back to try and kill Barry, so never accidentally killed **Nora**. Nora and **Henry** , however, had another child and thus a sister to Barry and together the four had a very atypical average family life; Barry went to college, got his masters and Amelia (preferring to go by the name Mille), Barry's sister, went on to start dating **Wally** , some three years her elder, much to the bemusement of both families who remained as close in this universe as in the TV show's – Francine is actually a neighbour to the Allens so they obviously saw a lot of the Wests, making Iris and Barry natural friends by the time they went to school; Iris too is engaged to Eddie, who never sacrificed himself as there was no need to stop Eobard Thawne…

So that leads me to **Harrison**. Never killed by the Reverse-Flash, he and his wife **Tess** went on create STAR Labs in the image they had always planned, and together they had two children – **Jesse** and **Belle** (both named after two alter-egos of Jesse Quick, whom Jesse Wells is named from on the actual show). Sadly, Tess died when Jesse hit eighteen (and Belle fifteen) and thus Harrison became a widower and single father to two wonderful daughters. Turning on the Particle Accelerator and changing the world due to the new science it could have presented was always going to be Harrison's way of honouring his late-wife, but as the accelerator never got that chance, he always looked to his forced new employers, the DEO, with bitterness – being the greatest mind of the twenty-first century, he was pretty much unwillingly employed by the DEO in their cause. Of course, the pay checks are pretty impressive, so that helps.

 **Astra** and **Non** are also in the SuperEarth universe, their plans with Myriad the same and unchanged, as mentioned in my final chapter. Fort Rozz is still in Nevada, and sadly Astra died like in the show – exactly in the same way, albeit with Alex defending her father and not J'onn. I also now need to shout out to **Lois** and **Clark** ( **Superman** ); their history is exactly the same as the sort we've grown to know today, including that of Metropolis itself, the only exception being my complete ripping off of _CharmedMillie_ 's coupling and having the pair be parents to two children; Jason and Ella. Kara shares godmother duties with Lucy, while James is sole godfather to both. Neither child can fly but have inherited some Super qualities from their father.

And there you have it! A brief history of all the characters we know and love from the two shows, with their own SuperEarth spin. Any more questions, I'm happy to make an additional 'Footnotes2' or something, so feel free to continue asking questions I may not have predicted the answers for, but I hope this did answer all your questions to this particular universe.

Now some people have been asking about if I plan a spin-off of either variety; SuperEarth with Kara and 'Barry 3' and/or Barry getting back to his Earth and what that could entail. Well I have ideas for both but I need the interest in one or the other to get me to continue. SuperEarth works fine by itself, teasing something new while not going too far, but to give you all a little extra tease as to what either could involve…

'SuperEarth Sequel – A New Flash' (actual title TBC) would feature Kara and Barry's friendship, with Wells pursuing in making his own 'Flash' and finding that sole candidate in Barry himself. How can this happen without a large particle accelerator explosion? There's a hint in the final chapter of SuperEarth. But where would this lead 'Barry 3'? He has no need to look for the impossible, to become the impossible, he's happy as is, which means SuperEarth's Flash could be a very differently motivated character to the one we know and love.

'SuperEarth Spinoff aka. Return to Earth-1' (see what I did there? Not the final title though) would indeed see Barry come back to his Earth a slightly changed man, but Zoom is no-where to be seen. Whether this takes place between seasons 2 and 3 of Flash remains to be seen, but for this story Barry would seek out his Earth's Kara in a similar way SuperEarth's Kara sought 'Barry 3' – but she is different to the Kara he knows. There is hope though, because the world needs more than one proper superhero. The world needs **Power Girl**!

If you want either, let me know and I'll find out which one is more popular to maybe write first. Don't be afraid to PM me thoughts too, I'm quiet deep in the 'Karry Universe' anyway (you might say) so that adding ideas to what I already have wouldn't change what basic idea I have formed – it may make them better too…


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